i just tried it, i think 40 seconds or more is pretty good. i got rid of a large and bothersome pimple right after this! if your blackheads are near the surface of your skin, most of it comes out. it didnt get all of my pimples, but it’s still pretty good. your acne goes a bit red after it, mine’s in the process of dying down right now. this is really simple and easy to do!